The proposed research project aims to characterize ultrastructural alterations which occur in renal and vascular cells after treatment with vinblastine sulfate, an oncolytic drug which influences the integrity of cytoplasmic microtubules. It is proposed that transmission and scanning electron microscopy be used to examine kidney tissue and blood vessels of rats given intravenous injections of vinblastine. The basis objectives are (1) to understand better the substructure of microtubules and vinblastine-induced structures comprised of microtubular protein, (2) to further our understanding of what functions microtubules perform in certain kidney cells, and (3) to characterize more fully some vinblastine-induced alterations which may shed light on the etiology of certain adverse side-effects of the chemotherapeutic use of this drug.